Greetings all,

I'm trying to put together a system where I can talk to my house. I'm aiming for a microphone in each room so I can give voice commands to the house such as "dim the lights" or "turn the TV on". I'm fine with the speech recognition side of things and I've cobbled together a simple test system using a small FM transmitter and an FM radio connected to the mic in on the soundcard of my PC.

What I'd like to do now is build some transmitter modules for each room. The FM I'm using is clearly illegal and rather too close on the dial to Radio 2! So what I'm after is a cheap, simple and legal transmitter and receiver. So far my googling has come up with modules like this http://www.quasaruk.co.uk/acatalog/A...ter_-_TX1.html
which looks great except it seems to be designed to transmit data rather than audio. Does anyone know of something similar for audio/analogue? The simpler it is the better. Ideally connections for mic, aerial and power and that's it.

WG.

http://cgi.ebay.co.uk/Signal-booster...QQcmdZViewItem

This may be helpful I can tell you about tuning, but I think this is legal. But its on eBay @ 99p and only 3hours left

In the US, there is a carve-out for <10 mW radiated power. Don't know about the UK, though.

Is FRS available in the UK? it runs in my mind it is. I bet thouse could be adapted. In the US, they are pretty cheap.

yeah, I think they use the family radio service band (frs).

Well thanks for the (rather disappointing) info about the legality of this and hence availability of easy to use modules.

Anyone got any ideas how to get fairly low quality mono audio from multiple rooms to one central point? Running new wiring is not really an option.

I hear that transmission over existing mains cabling is dreadful, plus I'd probably kill myself.

How about sticking a cheap ADC on the front of a radio module designed to send data and then a DAC at the receiving end?

Oh yeah, to some above, I feel I should point out I'm not planning on having long conversations with my house. Just issuing a few simple commands like:

"Lounge lights On"
"Coffee On"

or

"Open the bay doors Hal"

Hi Jim,

Walkie talkies are a good idea, thanks. I found a pair for £15 from Maplin which I may have a play with.

I take your point about other people being be able to tune in and while I have to admit that I lead the kind of life where anyone eavesdropping would probably die of boredom, I'd not considered they might be so sneaky as to record the house commands and re-transmit them. I may have to omit the "Unlock Front Door" and "Open the Safe" commands.

I'm still thinking that a DAC coupled with a data radio module might work and would also get round the eavesdropping problem. I think I’ll have a play with that first but if it doesn’t work I’ve got the walkie talkies to fall back on. “House, turn the lights on, over”

I'm not sure using walkie talkies for this application is legal, as the FCC limits the types of communication that can occur on the band not just the devices. So human to human usage is okay, but human to PC is probably technically illegal. It's considered a remote control application and covered under a different ruleset. The unlicensed bands (Wifi and Bluetooth) would likley have to be used to make it fully legal. A bluetooth setup would probably work best, but would be frightfully expensive and difficult to set up as you'd basically need a repeater for ever room of your house. Then again I don't go priceing this stuff on a regular basis so I'm not sure how technically feasable it is using bluetooth to set up a pico net of audio devices. bluetooth audio device specs are standard though so you should be able to get away with some pretty basic hardware. Try googling for basic bluetooth microphones.